The only black colored birds I was told about by the old timers was a family they referred as chocolate blood line that many would introduce to the Allen or Johnson family to speed them up! Still very good looking birds , if you raise chicks and handle them properly as they grow they will be big...
It’s not a show breed no matter what! It’s a fighting game breed - google roundhead game and you’ll see the difference between the families of roundheads
Picture below is the the color scheme of Lacey Roundhead , I would suspect that you got a Round Head- Hatch cross
The most common way to give Round heads toughness !
Game hens start laying around 6 months of age , also if you breed from them, even half game roosters will fight each other and bully your other roosters!
They do make the absolute best mothers, I have one I use to hatch my eggs under and seen her whipping a Tom cat - wish I had the event on...
Update , I have one baby that is looking like a spangled version of a barred rock and the rest is black that is out of the Lavender Ameraucana and Cream Legbar